1. Field of the Invention
The present invention relates generally to a mattress incorporating a headrest in which an infant's cranium is positioned while the infant is sleeping to prevent and correct cranial deformities. More specifically, the invention relates to a mattress incorporating a headrest for preventing and correcting any non-synostotic deformity of the side and posterior aspects of an infant's head.
2. Description of Related Art
At birth, the six cranial bones comprising an infant's skull are spaced far enough apart to allow the skull to rapidly grow during the first months of the infant's life. This spacing also allows the bones to overlap so the infant's head can pass through the birth canal without compressing, and thereby damaging, the infant's brain. Eventually—some time between three and six years of age—the cranial bones will fuse and remain fused for the rest of the child's life.
During an infant's normal growth, forces within the infant's skull are directed outward and are constant and equally distributed on the inner surface of the growing skull causing the skull to expand. Accordingly, a decrease of the intracranial pressure will cause a reduced head size. Similarly, an increase in intracranial pressure will cause an increased head size.
Fibrous bands of tissue, called cranial sutures, fill the space between the bones and connect the bones of the skull to each other. These cranial sutures are strong and elastic, providing a flexibility to the skull to allow rapid brain growth during the first months of life. Without the sutures, a child would suffer brain damage due to constriction of the brain during the period of normal growth.
During the first few months of an infants' life, however, the infant is most susceptible to the formation of synostotic or non-synostotic deformities in the cranium. Synostotic deformities are a result of craniosynostosis, which is a birth defect of the skull characterized by premature closure of one or more of the cranial sutures. Craniosynostosis can be hereditary or the result of a metabolic disease, and is characterized by an abnormally-shaped skull and potential for abnormal intracranial pressure, mental retardation, seizures, and blindness.
On the other hand, non-synostotic deformities, in which the cranial sutures remain open, are caused by environmental conditions, including premature birth, torticollis (twisting of the neck muscles beyond their normal position), or the preferred sleeping position of the child. In addition, neurological abnormalities, such as paralysis, cerebral palsy, or some sort of developmental delay, may predispose a child to cranial positioning problems. Non-synostotic deformities are also called positional deformities.
Synostotic and non-synostotic deformities manifest themselves in a variety of ways. Plagiocephaly, for example, is a cranial deformity resulting in an asymmetric head shape. Plagiocephaly consists of a focal area of flattening in the anterior or posterior aspect of one side of the head, which also commonly produces additional compensatory deformities in adjacent areas of the skull, skull base, and face, including the orbital (eye) and mandibular (jaw) structures. This deformity most commonly occurs in the posterior aspect of the head (posterior plagiocephaly), resulting in a focal area of flattening on that side and a compensatory prominence, or bulge, on the other side. In addition, the deformity produces anterior displacement of the ear, ear canal, temporomandibular (jaw) joint, forehead and orbital structures on the same side. Cranial deformities may also be classified, inter alia, as brachycephaly (a short, wide head shape), scaphocephaly (a long, narrow head shape), and turricephaly (a pointed head shape).
Non-synostotic posterior plagiocephaly is a very common problem for which parents seek evaluation and recommendations from their family physician or pediatrician. The incidence of this abnormality has increased significantly since publication of recommendations by the American Academy of Pediatrics that neonates (infants) should be put to sleep on their back rather than face down. These recommendations were made to reduce the incidence of Sudden Infant Death Syndrome (SIDS) by eliminating airway and respiratory compromise in the prone (face-down) position, which the Academy considered a possible contributor to the SIDS problem.
The usual method of attempting to treat these deformities involves trying to reposition the child during sleep. The most common adjuncts available to assist with this treatment are flat- and wedge-shaped foam pads. For example, U.S. Pat. No. 6,473,923 (filed Nov. 22, 2000) (issued Nov. 5, 2002) discloses a body pillow and head positioner attached to a mat. The device is intended to maintain the infant's supine position while reducing the risk of positional plagiocephaly by causing the head to rotate to the side while maintaining the infant's supine position.
Simply put, repositioning, even with foam padding, is ineffective for treating or preventing these deformities, and even after treatment most children do not obtain a perfectly normal head shape. Repositioning merely distributes or disperses the forces over a larger area of the head. The foam padding remains in contact with the skin and conforms the head to an abnormal shape. Due to this ineffectiveness, a large number of these children require additional treatment from five to ten months of age due to persistent or progressive deformities.
The additional treatment most often is by application of a custom-made external orthosis, or helmet. See, e.g., Corrective Infant Helmet, U.S. Pat. No. 6,592,536 (filed Jan. 7, 2000) (issued Jul. 15, 2003); Therapeutic and Protective Infant Helmets, U.S. Pat. No. 4,776,324 (filed Apr. 17, 1998) (issued Oct. 11, 1998). Such devices provide an expanded area over the site of the deformity, thereby allowing for correction of the deformity over a three- to six-month period of time related to brain and skull growth and subsequent reshaping. This prolonged time of use is necessary because of the reduced rate of brain and skull growth during the six- to twelve-month time frame. Due to a decrease in the rate of brain and skull growth to approximate fifty percent of the rate from birth to six months and increased stiffness of bones and cranial sutures, the recommendation is to wear the helmet continuously for twenty-three hours each day for up to twelve months. But despite extended use of these helmets, deformities rarely return to a normal shape. In addition, many health insurance companies and programs refuse to pay for these devices, leaving a large number of infants with no available treatment because of the relatively high cost of the helmets.
Another approach to correcting cranial deformities is to soften the material on which the infant's head rests by using a foam pad or memory foam pillow. This method allows the redistribution of inwardly directed forces over a slightly larger surface area, but fails to adequately correct cranial deformities because the softened material conforms to the head shape. The material still contacts, and therefore applies forces to, flattened areas instead of only the abnormal cranial bulges. Preventing cranial deformities with this approach is also ineffective because forces continue to act directly on a focused area of the head. Forces acting on a smaller area of the head results in cranial flattening, and therefore an abnormal head shape, because the head conforms to the shape of the material at the point of contact.
Still another approach is to suspend the infant's head on a flexible material, which, for example, may be a net with an open weave that keeps the infant's head slightly elevated over the resting surface. See Method and Apparatus to Prevent Positional Plagiocephaly in Infants, U.S. Pat. No. 6,052,849 (filed Mar. 18, 1999) (issued Apr. 25, 2000). Although the use of an elastic stretchable material or netting may be slightly better than regular foam for preventing the development of flattened areas, these devices do not promote normal shaping due to the continuous application of external forces directed at a smaller posterior aspect of the infant's head. As with the “softened material” approach previously described, forces acting on a smaller area of the head results in cranial flattening because the head conforms to the shape of the stretched material, thus resulting in an abnormal head shape in which the frontal areas are wider than the posterior aspect of the head.
After ten to twelve months of age, little, if any, correction of a cranial deformity can be accomplished with non-operative treatment because of reduced velocity of brain and skull growth, increased thickness of bone, and reduced flexibility of the cranial sutures. Surgical intervention is typically the only effective treatment for moderate to severe deformities in children over twelve months of age.
The prior art for treating this condition does not directly address the cause of the problem, and therefore does not effectively treat the condition. All other products and devices, including foam, elastic (and therefore flexible) material or netting, merely distribute or disperse forces over a larger area of the head. Because these products and devices remain in contact with the skin, they therefore conform the cranium to the abnormal shape. Thus, the prior art does not remove or eliminate the external forces at flattened areas of the cranium, but rather maintains an abnormal cranial shape and promotes a static deformity.
Currently there is no specific apparatus available to provide effective corrective and preventative treatment for non-synostotic cranial deformities in the age range of birth to five months. To avoid the difficulties and pitfalls associated with currently available devices aimed at treating non-synostotic cranial deformities, the present invention discloses a corrective headrest for use at the very first recognition of development of a deformity. The headrest and method allow effective treatment during the rapid period of brain and skull growth (birth to six months), thereby providing rapid correction of the deformity. Children with predisposing conditions possibly require prolonged treatment. Early effective treatment is the key to providing complete correction of these deformities.